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How To Fix Car Stereo Draining Battery

Is your car battery draining repeatedly even though you replace it regularly? You might have checked all the possible causes but still couldn't find the core issue. A faulty car stereo is probably the last thing you'll think of, but that's one of the main reasons why car batteries keep draining overnight.

Now, the question is, how to fix car stereo draining battery? Luckily, there are several ways including fixing the battery wiring, using a switched fuse, installing an additional battery, replacing the stereo, turning off the sleep mode, etc.

Here, we'll tell you how to tell if your car stereo is draining the battery, all the possible reasons why it might happen, and how to prevent the stereo from using battery power. So, without further ado, let's get right in.

As you know, car batteries can drain for tons of different reasons. So, how do you know if your car stereo is causing a dead battery? Don't worry; a few signs can help you with this. You'll face these problems if your car stereo is draining its battery-

Battery Light Turned On

Of course, your vehicle's main unit will identify unusual battery usage. So, it will alert you immediately and you'll notice the battery alert light turned on. In some cases, it simply shows a red sign on the dashboard.

Either way, it's the easiest way to identify the draining battery issue.

Difficulty In Starting

Another common sign of excessive battery usage is that you won't be able to start your car smoothly. Your battery supplies the required power to start the car. Therefore, a drained battery will fail to provide sufficient power for ignition.

Cranking Engine

Even if the car engine ignites, it will make horrible cranking noises for a few moments before completely starting. Also, your car will struggle a lot due to the lack of electric current.

Dimmed Lights

From your car interior lights to its headlights, every light source will lose its brightness if your stereo is draining the car battery. So, if you notice that your car headlights are dimming, check out the stereo and battery wirings.

A General Solution To Fixing Car Draining Battery

Of course, you need to identify the problem first and then proceed to a suitable solution. However, if you're in an emergency, this urgent fix will help you quickly prevent your car stereo from drawing battery power.

For this, we will check the battery and stereo wiring and fix any faulty or misplaced cable. Keep in mind that this solution works for general battery issues only. So, it might not work for your car and you need to specify the real cause in that case.

Here's the general solution-

Step One: Take Off Your Car Stereo

First things first, turn off your car's ignition and disconnect the negative wire from the battery. This will avoid unwanted accidents while you're working. After that, you need to remove the stereo using a flathead screwdriver.

Unscrew the bolts from the stereo and pop off the trim. Finally, grab the stereo and pull it out from its socket. Place the stereo on your car seat or a safe place.

Take Off Your Car Stereo

Step Two: Check the Wiring

On the back portion of your stereo, there is a wiring harness. While installing a new stereo, you might have misplaced one or two wires which Is causing the battery to drain. So, now you need to fix the wires and place them correctly.

First, look for the red, black, and yellow wires. Connect the red wire to a switch that links with the 12V line coming for one of the positive wires from your car.

The yellow wire will go with the 12V positive terminal of your car battery. As for the black wire, connect it to the negative battery terminal.

This should fix the wiring and battery draining issue.

Check car stereo wiring

Step Three: Test Wire Continuity

If the battery issue persists even after hooking up all the wires correctly, you need to check the wires for continuity. Take a voltmeter to check all the wiring between the car stereo and battery.

A missing signal from the wires indicates faulty, loose, or broken wiring.

Step Four: Fix Faulty Wires

To fix broken wires, strip them off and reconnect. Faulty wires should be removed and replaced by new ones. If any wire has loosened, tighten it or consider using a new one. And your car stereo won't be able to outsource power from the battery anymore.

Some Specific Causes and Their Solution

Apart from the wiring issue, there are a few other reasons for draining the battery. Here are the specific causes and easy solutions for you-

Cause One: Worn-Out Battery and Stereo Components

Besides the wires, other components connecting the car battery and stereo can cause battery draining. Check for worn-out battery terminals, stripped insulation, and other parts of the electric system to identify the root of this problem.

Also, inspect all the stereo relays and internal circuit boards for any malfunction.

Easy Fixes: Once you have located the corroded or faulty component, you can easily replace it. You can repair the battery components, but fixing the stereo requires deep knowledge of the system. So, it's better to replace the stereo instead of repairing it.

Cause Two: Using the Wrong Fuse Port

The fuse of your car is of two types: constant and alternate or switched. While installing a stereo, you must connect it to the switched fuse. This way, the stereo won't be able to draw power from your car battery when the engine Is off.

If you have mistakenly hooked up the stereo with a constant switch, that might be the cause why you're car battery is draining faster.

Using the Wrong Fuse Port
Easy Fixes: Use a tester to see which fuse type is attached to your car stereo. If the alignment is wrong, simply disconnect the fuse box from the stereo and hook it up again with the switched fuse.

Cause Three: Under-powered Car Battery

Every stereo requires a minimum amount of battery power to function optimally. Sometimes, upgrading to a more advanced stereo can demand more battery power. But, your battery might be underpowered for the stereo.

In that case, the high-powered stereo will draw more amperage from the battery causing it to drain faster than usual.

Easy Fixes: To solve this battery power issue, you can replace your under powered car battery with a bigger and more powerful one. Or, installing an additional battery will also help. If you ask me, I'll suggest going for a secondary battery as it's way easier than fitting a bigger one.

Cause Four: Sleep Mode Turned On

You have probably turned on the sleep mode on your dashboard to save power.

Sometimes it causes the stereo to remain on even when your car engine is off. 

Hence, it slowly draws power that often goes unnoticed until you end up with a flat battery.

Sleep Mode Turned On
Easy Fixes: The solution here is simple. Refer to your owner's manual and turn off the 'power saving' or 'sleep' mode.

Final Words

So, now you know how to fix car stereo draining battery. A regular inspection of the stereo and battery terminals, wirings, and internal components can save your battery from dying no matter how much power the stereo draws.

If you see any of the signs of battery draining mentioned above, take immediate action before ending up with a dead battery. Follow the easy fixes and you'll be able to save your car battery without spending much.

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